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(11) | EP 0 169 361 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Pasteurization process and apparatus |
(57) This application relates to a precision tunnel pasteurization process in which the
spray density is above about 285.19 I./min./m2 (7 gal./min./ft.2) of processing area and the spray is uniformly distributed over the processing area
of the pasteurizer whereby the spray water heats the beer to 60-61.66°C (140 - 143"F)
and then cools the beer to 21.11-29.44°C (70 - 85°F). The spray nozzles are positioned
on staggered centers having 22.86-30.48 cm. (9 - 12 inch) longitudinal spacing and
15.24 cm. (6 inch) transverse spacing with 7.62 cm. (3 inch) spacing from side walls
and the nozzle bore is 0.95 cm (318 inch). The nozzle pressure is about 0.352-0.422
kg/cm2 (5 psig to 6 psig) and the spray nozzles are the type which are the least likely
to become clogged. The overlapping hollow cone sprays produce a very uniform spray
density at the elevation of the top of the cans or bottles. The improved pasteurizer also has the first heating zone regenerative with the first cooling zone. The advantages of this arrangement are particularly significant on a double deck pasteurizer with sprays only above the top deck. The spray temperature of the lower deck of the first cooling zone is higher than that supplied to the upper deck. The final result is to minimize the total accumulated P.U. difference between decks to less than 3 P.U. This uniformity in P.U. between decks is possible with product temperatures on the lower deck in slight excess of the required 60°C (140°F) minimum peak product temperature. |